90% of the archive is taken by png textures and mp3 music: filesize depends on data compression ratio, not on the actual duration of the show.
A loop option or crap quality compression (jpg textures, 128 kbps soundtrack) will help for those who feel like they have been robbed and might enjoy a better size/length ratio.

Also, most of the textures are ridiculously large by typical demo standards. Furthermore, yes, this could've been longer for nearly the same filesize... but how many chairs can one man take at a time?

As for the screenshot: it's a file that was in the zip archive. Somebody managed to put 'a' and 'WTF' together and concluded it was a screenshot of the demo or something. It looks silly enough, so let's keep it like that :)